Retractable sidewall-valve curing pin



Feb. 23, 1965 A. H. GOLLINIGS RETRACTABLE SIDEWALL-VALVE CURING PIN 2Sheets-Sheet 1 Original Filed Nov. 19, 1958 INVENTOR. ARCHIE H.6OLLINGSKQZZW FIG.2

ATTY.

Feb. 23, 1965 A. H. GOLLINGS 3,170,133

RETRACTABLE SIDEWALL-VALVE CURING PIN Original Filed Nov. 19. 1958 2Sheets-Sheet 2 llHll II I 5 1 l f FIG.3 i

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ARCHIE H.GOLLINGS ray/4M ATTY.

United States Patent 3,170,188 RETRACTABLE SmEWALL-VALVE CURING PINArchie H. Gollings, Akron, Ohio, assignor to The Firestone Tire & RubberCompany, Akron, Ohio, a corporation of Ohio Continuation of applicationSer. No. 774,941, Nov. 19, 1958. This application Oct. 25, 1962, Ser.No. 234,005 1 Claim. (Cl. 18-2) This invention relates to thevulcanization of pnuematic tires and more specifically to the forming ofopenings in the side walls of tires such as for tire sidewall inflationvalves.

The present application is a continuation of my prior application SerialNumber 774,941, filed November 19, 1958, which is now abandoned.

Heretofore, in forming openings in tire Walls it Was common practice toprovide the inside of a tire mold cavity with a stationary curing pinagainst which the tire was expanded to form a hole in the sidewall of atire. Diiiiculty was encountered with this method due to the fact thatthe pin was forced through the tire sidewall as the tire was beingexpanded in the tire mold, to cause, in many cases, tearing of the coldtire sidewall and tire cords which weakened the tire and ultimatelycaused tire fail ure. Another objection was that a larger than desiredopening was frequently formed. Another objection to this method was thatwhile the tire was being removed from the mold, the tire sidewall wasfrequently raked and damaged by the protruding curing pin, and this alsoresulted in premature tire failure.

This invention overcomes the aforementioned difiiculties by providing aretractable curing pin to form an opening in the tire sidewall. Thecuring pin is retained in withdrawn position until the unvulcanized tireis fully expanded by vulcanizing fluid under pressure against the wallsof the mold. The pin is then introduced into and through the sidewall ofthe tire after the tire has been heated from the curing heat andpressure. Prior to the release of curing pressure, the pin is retractedto permit re moval of the tire from the mold, without damage to thetire, when the mold is opened.

It is therefore an object of this invention to provide improved meansfor forming a hole in the sidewall of a tire.

Another object is to provide hole forming means Which will not injurethe tire carcass during operation.

Another object is to provide a hole forming means which will evenlydisplace tire cords of the ply fabric around the hole being formed.

Another object is to provide a hole forming means which will provide anaccurate opening.

These and other objects will become more apparent upon reference to thefollowing specification and drawings in which:

FIGURE 1 is a sectional view of an automobile tire incorporating asidewall inflation valve.

FIGURE 2 is a fragmentary sectional view of a vulcanizing mold showing asidewall valve hole being formed in a tire.

FIGURE 3 is an enlarged fragmentary View of the hole forming mechanismof the invention after the hole has been formed.

Referring to FIGURE 1, a tubeless the is shown comprised of a pair ofinextensible bead wire bundles 11, 11 suitably anchored and adhered to afabric body portion 12. The tire It) has a tread portion 13 merging intosidewall-s 14 and 15. The inner periphery of tire it) is provided withan air impervious innerliner. Sidewall 14 is provided with a hole orseat 16 in which is mounted a sidewall inflation valve 17.

Referring now to FIGURE 2, a tire vulcanizing mold assembly 18 is shownas comprising an upper mold shell 19 and a lower mold shell 20 defininga tire molding cavity 21 which confines the tire 10 duringvulcanization. Upper mold shell 19 is secured to a steam platen 22, andlower mold shell 20 is secured to a steam platen 23.

Mounted on the upper portion of the mold 18 is an air cylinder 25,having a piston rod 26, pivotally mounted to one end of an actuatinglever 27 by pin 30. The lever 27 is pivotally mounted in a bracket 28 bypin 29. The opposite end of arm 27 is provided with slot which receivespin 32 for pivotal motion of a curing pin plunger assembly 33.

Plunger assembly 33 is confined within passage 36 passing through theupper platen 22 and relief plug 38 in upper mold shell 19. The plunger33 is provided with suitable suitable packing or seals 4'!) to provide afluid-tight fit between the passage 36 and the plunger 33.

Plunger assembly 33 comprises a pair of oppositely threaded rods 34 and35 threaded into a complementarily threaded sleeve 37 to facilitateadjustment of the length of the plunger assembly. When sleeve .37 isturned in one direction, it will extend the threaded rods 34 and 35;when turned in the opposite direction, the sleeve will retract thethreaded rods 34 and 35. At the outermost end and integral with rod 35'is a curing pin 41 reciprocated through plunger 33 by arm 27 and aircylinder 25.

In operation of the invention the unvulcanized tire carcass is placed inthe mold 18, the mold is closed, and vulcanizing fluid under pressure isintroduced into the tire forcing the tire outwardly against the walls ofthe mold shells 19, Zil. Cylinder 25 is then actuated through suitablecontrol means, not shown, to slide the end of pin 41 out of passage asand into and through the sidewall 14 of the tire.

Pin 41 remains in this position throughout the cure and is retractedjust prior to the release of the internal curing pressure. With the pin41 in the retracted position, the mold is opened and the tire 19 isremoved. therefrom with ease and without damage to the side wall 14 ofthe tire 10. Sidewall valve 17 is then inserted in hole 16 completingthe operation.

While one modification of the invention has been shown and described, itwill be apparent that other modifications may occur to those skilled inthe art without departing from the scope of the invention, the essentialfeatures of which are summarized in the appended claim.

What I claim is:

Apparatus for forming a valve opening in the sidewall of a tire whilesaid tire is undergoing the process of vulcanization in a mold,comprising a single passage in the mold radially inwardly of the treadarea of the tire and substantially normal to the tire sidewall, a sleeveslidable in said passage, a plunger assembly adapted for reciprocalmotion axially of said single passage comprising first and second rodsoppositely threaded into said sleeve, the first of said rods terminatingin a curing pin having a closed end, and articulating means toselectively confine the length of said curing pin completely to saidpassage and to move said pin through the tire sidewall in a dire"- tionsubstantially normal thereto.

References Cited by the Examiner UNITED STATES PATENTS 3,096,541 7/63Sindelar 182 MICHAEL V. BRINDISI, Primary Examiner.

